Design of A Microwave/Millimeter-Wave Shared-Aperture Antenna by Hybridizing Series-fed Antenna Array and Leaky-wave Antenna

Applications operating in both microwave (MW) and millimeter-wave (MMW) are important for future wireless communication systems. To fulfill the requirements of dual-band applications, a novel shared-aperture antenna is proposed with broadside radiation in both MW and MMW bands. Series-fed planar inverted-L antenna (PILA) elements are symmetrically placed to design a MW-band array with broadside radiation. A novel MMW band leaky-wave antenna is integrated into the PILA array as a transmission line in the MW band. Our analysis reveals that the proposed leaky-wave antenna can suppress unwanted radiation from the MW array in the MMW band. Therefore, the MW array and the MMW leaky-wave antenna can be integrated into a shared-aperture for a compact design. The leaky-wave antenna is designed with a non-uniform configuration to mitigate the open-stopband. The fabricated prototype produces broadside radiation in the MW band from 3.46 to 3.72 GHz, with a peak gain of 7.6 dBi. Frequency-scanning beams are generated near broadside in the MMW band. Within the operating band from 30 to 40 GHz, the main beam scans from -21° to 14° with a realized gain varying between 12.5 dBi and 15.7 dBi.